Many patients develop stones within their common bile, urinary, renal or ureteral systems. These stones may block ducts and cause great pain and therefore must be removed. Several approaches are available for treating such stones.
The traditional approach has been open surgery where multiple incisions are made to approach and remove the stone from the duct. This treatment results in a relatively long recovery period for the patient, and has fallen into disfavor.
Currently, extra-corporeal shock wave lithotripsy (ESWL) has become the treatment of choice for many patients. In these devices the patient is subjected to shock waves. The shock waves pass through the patients' skin and break up the stones. However, there are stones which cannot be removed by this technique because of their location, volume or composition. In general, these difficult stones are candidates for alternate surgical approaches.
Among the alternate lithotriptors are those which operate on electro-hydraulic, pneumatic and ultrasonic principles, as well as devices which use laser energy to fragment the stones. U.S. Pat. No. 5,160,336 to Favre and U.S. Pat. No. 5,449,363 to Brust et al. which disclose pneumatically driven devices which are useful alternatives to conventional open surgery. However, even with these devices, there is a need for a lithotripsy system which can deliver high energy to the stones and operate with small and flexible endoscopes.